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Full text of "The manufacture and properties of iron and steel"

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Iron ore is natural iron rust. It is a combination o-f iron and oxygen, and if we take away the oxygen the iron is left alone. If a large heap of charcoal be set on fire and urged by a hand bellows, and if iron ore be added to the heap, the oxygen of the ore will combine with, the charcoal, while the metallic iron will separate in pasty globules. The temperature of such fire will not be high enough to melt the iron; it will not even be high enough to cause the iron to absorb a considerable quantity of carbon and thereby become pig-iron, but it will be high enough to cause the pasty globules to stick or weld together. In this way for thousands of years iron was made all over the world. Here and there improvements were made by protecting and confining the fire by brick walls, either in a hole below the ground or in a furnace above the level, and sometimes large bellows were used, driven by water power, but the scale of working was always small. The Catalan forge, which was in use in more or less modified form in every country of the world, was nothing but a, hole in the ground about two feet square and two feet deep. This was filled with charcoal and ore, sometimes carefully arranged in two vertical parallel layers, and sometimes mixed together.; a blast of air inclined downward, the tuyere being pushed into the midst of the mass, completed the apparatus. In America this rude contrivance was used quite extensively in recent years for making charcoal blooms; in 1882 the output was 48,000 tons in the United- State's, and as late as 1888 it was 14,000 tons.
In Germany'the early iron-makers increased the size of the furnaces, and in the sixteenth century some were fifteen feet high and five feet in diameter, but the pasty ball was still the end desired, and the whole front of the furnace was torn out each time to pull out the mass, which was then forged into bars of wrought-iron. At a later time, possibly in the sixteenth, and perhaps not till the